Z3 is a theorem prover from Microsoft Research.
Z3 is licensed under the MIT license. 
Z3 can be built using Visual Studio Command Prompt and make/g++.

1) Building Z3 on Windows using Visual Studio Command Prompt
   
32-bit builds, start with:

   python scripts/mk_make.py

or instead, for a 64-bit build:

   python scripts/mk_make.py -x

then:

   cd build
   nmake

2) Building Z3 using make/g++ and Python
Execute:

   python scripts/mk_make.py
   cd build
   make
   sudo make install

By default, it will install z3 executable at PREFIX/bin, libraries at PREFIX/lib, and include files at PREFIX/include,
where PREFIX is the installation prefix used for installing Python in your system.
It is usually /usr for most Linux distros, and /usr/local for FreeBSD.
Use the following commands to install in a different prefix (e.g., /home/leo)

  python scripts/mk_make.py --prefix=/home/leo
  cd build
  make
  make install

In this example, the Z3 Python bindings will be stored at /home/leo/lib/pythonX.Y/dist-packages,
where X.Y corresponds to the python version in your system.

To uninstall Z3, use

  sudo make uninstall

4) Building Z3 using clang and clang++ on Linux/OSX
Remark: clang does not support OpenMP yet.   

   CXX=clang++ CC=clang python scripts/mk_make.py
   cd build
   make


To clean Z3 you can delete the build directory and run the mk_make.py script again.